35 hp Johnson Lean Sneeze / Pop causes

[mato0010]

Re: 35 hp Johnson Lean Sneeze / Pop causes

Yes I did replace with new rings as well. Pretty much everything that I could replace I did. What do you mean by the rings are not seated yet? The only thing I could think was that all of the parts have a coat of oil on them which is causing the more difficulty turning but Im not sure what you mean by seated?

 

[bktheking]

Re: 35 hp Johnson Lean Sneeze / Pop causes

I hope you honed the cylinder walls to get rid of the glaze and give the new rings a new surface.

Here's an article to explain why:

http://www.mattituck.com/articles/engbrkin.htm

Ignore the blowby part, oil is in the gas but it explains the idea.

 

[Cofe]

Re: 35 hp Johnson Lean Sneeze / Pop causes

Looks like you're doing a fine job. I am with BK on making sure to hone the cylinders before you install the pistons. Also while you are at it, it would be a good idea to replace all your rubber hoses. You will be thankful you did.

Be certain to ask if you have any questions, there are quite a few well seasoned motor heads here that can help.

 

[mato0010]

Re: 35 hp Johnson Lean Sneeze / Pop causes

Yes, I had the pistons honed to .030 oversize as well as had the head resurfaced. Bought .030 oversized pistons and rings. Like I said, pretty much replaced everything. If Im going to spend the time and effort to do it then I my as well do it right.

 

[mato0010]

Re: 35 hp Johnson Lean Sneeze / Pop causes

Cofe,
Like what hoses are you recommending. I was debating on replacing the fuel hoses because they look in good condition and fuel flows well but I thought if I already have the motor out then it should be easy to do it now. That would be the hose going from side of motor case to fuel filter, as well as hose going from fuel filter to carburetor. Should I also replace the small oil hoses (one that goes from reed valve to fuel intake, and one that goes from top crankcase to bottom of crankcase? Those are the only hoses I can think of. Would you replace all? Any others?

 

[Cofe]

Re: 35 hp Johnson Lean Sneeze / Pop causes

Old hoses were not ethanol safe. They break down and get rubber in the carb. etc. Even the hoses and pump bulb to the tank.
I would replace all the hoses I could, and I think what you are calling the fuel filter is the fuel pump. Unless there is a added inline filter.

Also note, that the plastic ties on the fuel lines are special rounded ties. You can get them from a marine shop, or here at IBoats.

 

[mato0010]

Re: 35 hp Johnson Lean Sneeze / Pop causes

Here is the final wrap up. Got the motor all put back together (took a lot longer putting together than I thought), eventually ended up getting it started and low an behold I still had a lean sneeze. It was by far less often and less intense than before but there was definitely still a lean sneeze. By then I needed to gather my thoughts and composure. Yesterday I then decided to change out the fuel lines as Cofe had mentioned. Looked like there were areas that showed some cracking and could have been causing. I also tried adjusting the throttle valve following the steps in my service manual but in doing so I realized that my throttle was not able to completely close. It was remaining partially open. This also could have been throwing off my air/fuel mixture. Once I replaced the fuel lines and adjusted the throttle valve so it completely closes I started it back up and the lean sneeze was gone! Finally. A huge sense of relief!

Essentially after rebuilding everything I look back and I know that there were several things that needed to be replaced so it was only a matter of time. So even though the lean sneeze might not have been directly caused from the pistons, it was best that I dug that deep to make sure everything was good.

Now here is where I am at. I have a video posted of the motor running. Please anyone check this out and give me your thoughts. Sounds to me like there is a small ticking noise. More obvious on the port side of the motor. Fast repeating ticking that you have to have the volume up on the video to hear. I torqued everything to specs but now wondering if there might be play where the connecting rod links onto the crankshaft journals. Or possibly where the connecting rod connects onto the wrist pins of the piston. Before I had mentioned that when I put the new pistons and wrist pins on to the existing connecting rods, there was a little angle where the rods were not parallel to the inside of the pistons. The wrist pins went in smooth and everything moved good but Im concerned that the non-perfect alingment might also be causing that ticking noise. All these parts were new except for the connecting rods/arms so could my connecting rods have been twisted? Here is a drawing of what I am trying to describe.

Also here is a link to the you tube video of the motor running.

http://www.youtube.com/watch?v=t6QQD-bg95w

Thanks everyone.

 

[bktheking]

Re: 35 hp Johnson Lean Sneeze / Pop causes

When you pulled the pistons out, did you keep the rod caps together (same orientation as removed) and on the same piston????

Did you check to see if the rods were true?

 

[Cofe]

Re: 35 hp Johnson Lean Sneeze / Pop causes

Make sure that you follow the break in procedure for your motor. It should be in the manual.

Yes need to know what BK asked. Correct rod/cap orientation is very important.

 

[mato0010]

Re: 35 hp Johnson Lean Sneeze / Pop causes

Yes, I made 100% sure that the connecting rod caps which go over the bearings at the journals were on the same piston and exactly the same way. My service manual specifically said to make sure of this because they are specific to that piston and in that direction. The rod caps actually have markings on them to make sure you put them together the same way. Also once I got them together I made sure to check that they were perfectly aligned by running a pencil along all of the sides and chamfered edges to make sure that it was aligned perfectly. The service manual covered this so I paid extra attention to making sure all 4 peices went back to the same location and perfectly aligned.

But what I was talking about is on the other end of the connecting rod, where the wrist pin goes through the rod end.

I did not check to see if the rods were true because honestly I didnt think anything could have been wrong with the rods and nothing was mentioned of this in my manual. They both looked good but it was when I only had the rod attached to the piston that I could see that angled gap. FR mentioned that it could have been the casting of the piston.

 

[Cofe]

Re: 35 hp Johnson Lean Sneeze / Pop causes

The pistons should have a top orientation identification notch. If the rods were placed in the proper orientation to the pistons, everything should be right.

 

[mato0010]

Re: 35 hp Johnson Lean Sneeze / Pop causes

Actually my manual said that the pistons have a "LOOSE" marked on the bottom side of the inside of the piston. When I removed them, I saw the loose marking but on the new pistons it did not have that marked. But the pistons could only go one way because the head end of the pistons have an orientation that was specific to facing either the intake side or exhaust side. So I put them in the same direction. Also the connection rods can only go one way too because there is a small oil hole in the rod which needs to be on the top. So putting those 2 together in that orientation there were no differences from its original orientation.

 

[Cofe]

Re: 35 hp Johnson Lean Sneeze / Pop causes

Sounds like you kept a keen eye on things, and that is good. Just a note to make sure you follow the break in procedures.

 

[mato0010]

Re: 35 hp Johnson Lean Sneeze / Pop causes

Yup, I was planning to take it out tonight (pending the rain holds off) and following the break in procedure. I had it running at idle for about 15 minutes in my driveway yesterday.

Should I still put in double the oil? Like I mentioned, my service manual says to use 50:1 during break in. That is what I always use so why would they make sure to note it if its not different. Should I run 25:1 instead. Does anyone have a manual of that year similar motor and does it say 50:1 or 25:1 during break in?

 

[bktheking]

Re: 35 hp Johnson Lean Sneeze / Pop causes

Yup, I agree, casting of the piston. I listened to your video and had difficult time hearing any type of tick. Keep in mind you just rebuilt the motor, give it some time to break in.

 

[mato0010]

Re: 35 hp Johnson Lean Sneeze / Pop causes

Thanks! Whew. You guys are ALL awesome. Hopefully Ill get many of years out of this motor. To think that its a 1976 and the only setbacks are cosmetic....Im ok with that. Fish on!

 

[bktheking]

Re: 35 hp Johnson Lean Sneeze / Pop causes

If it were me I'd run more oil in it for the first couple of tanks just to be safe.

 

[mato0010]

Re: 35 hp Johnson Lean Sneeze / Pop causes

OK, I put in 3 gallons of 25:1 mix yesterday and will run that during break in. Then I will switch back to 50:1. Cant hurt it right? Here is a pdf of the break in procedure from my service manual. Weird why it would tell me to run 50:1 during normal use and ALSO 50:1 during break in procedure. Could this be a possible error in my service manual?

 

[bktheking]

Re: 35 hp Johnson Lean Sneeze / Pop causes

Here is a Tohatsu link stating the double up issue:

http://www.tohatsu-outboards.com/outboard-break-in-chart.htm

Yamaha pre mix break in:

General Engine Break-in Key Points
- All Models


Proper engine break-in can increase the life of
any engine. The Yamaha Engine Break-in
Procedure is designed to maintain engine
component temperatures within an acceptable
range to provide the best engine life expectancy.
The detailed engine break-in procedure is
explained in the Owner's Manual for each
engine. Some key points are as follows:
Use 50:1 premix with oil injected models for
the first 10 hours of operation. (25:l for premix
models.)
. Let the engine idle for the first 10 minutes of
operation.


50:1 sounds like oil injection to me.

 

[mato0010]

Re: 35 hp Johnson Lean Sneeze / Pop causes

Here is the page from my manual. Apparently the pdf file was too big so I needed to convert it to a jpg.